code: def _norm_args(norm):
      """
      Returns the proper normalization parameter values.
  
      Possible `norm` values are "backward" (alias of None), "ortho",
      "forward".
  
      This function is used by both the builders and the interfaces.
  
      """
      if norm == "ortho":
          ortho = True
          normalise_idft = False
      elif norm is None or norm == "backward":
          ortho = False
          normalise_idft = True
      elif norm == "forward":
          ortho = False
          normalise_idft = False
      else:
          raise ValueError(
              f'Invalid norm value {norm}; should be "ortho", '
              '"backward" or "forward".'
          )
      return dict(normalise_idft=normalise_idft, ortho=ortho)
  
file_path: py-fftw/pyfftw/builders/_utils.py
imports: import multiprocessing
  import pyfftw
  import numpy
  import warnings
  from ..None import _threading_type
  from ..None import config
label_desc: Use image node_id 3 for calling a global function with example usage: _norm_args(norm) and returns: dict